TLR7 and influenza: The hypothesis that live-attenuated vaccines could provide short-term non-specific protection against unrelated infections is supported by the data that the live-attenuated polio virus existing in the OPV, containing single-stranded RNA with the ability to stimulate TLR-7 and -8, results in production of pro-inflammatory cytokines and type I IFNs and leads to temporary protection against influenza (as reported by Voroshilova and Chumakov3) and SARS-CoV-2 (as reported by Habibzadeh et al).5,6 The pathogenesis of polio virus, influenza virus, and SARS-CoV-2 infections are quite different.